Agent MCP Directory

server/discover

server/discover: The 2026-07-28 RPC every server MUST implement to advertise supported protocol versions, capabilities and identity. Example: Clients may call it first or use it to probe older stdio servers. Next in the glossary is Stateless MCP: The 2026-07-28 model with no initialize handshake and no Mcp-Session-Id; each request carries version and capabilities in _meta.

Definition

The 2026-07-28 RPC every server MUST implement to advertise supported protocol versions, capabilities and identity.

Example, with source

Clients may call it first or use it to probe older stdio servers. (modelcontextprotocol.io, read 4 November 2026)

Neighbouring terms

  • server.json: The registry metadata file for one server: name, version, remotes, packages, website and repository.
  • Stateless MCP: The 2026-07-28 model with no initialize handshake and no Mcp-Session-Id; each request carries version and capabilities in _meta.
  • stdio transport: The MCP binding where a client launches the server as a subprocess and exchanges newline-delimited JSON-RPC over standard streams.